In-cell touch organic light-emitting diode display device

ABSTRACT

A display device includes a pixel array including touch blocks; a plurality of test pads in a bezel area outside the pixel array for performing a pixel test and a touch block test; a plurality of pixel test lines and a plurality of touch block test lines connected to the test pads within the pixel array; a switching unit between the test pads and the pixel test lines and the touch block test lines and applying a test signal to any one of the pixel test lines and the touch block test lines; a pixel test switching pad in the bezel area and providing a control signal for testing pixel operation in the pixel array to the switching unit; and a touch block test switching pad in the bezel area and providing a control signal for testing the touch blocks within the pixel array to the switching unit.

The present application is a Continuation of copending U.S. Pat.Application No. 17/855,731, filed on Jun. 30, 2022, which is aContinuation of U.S. Pat. Application No. 17/127,397, filed on Dec. 18,2020, now U.S. Pat. No. 11,386,821, which claims the benefit of KoreanPatent Application No. 10-2019-0180108, filed Dec. 31, 2019. Each of theabove prior U.S. and Korean patent applications is hereby incorporatedby reference.

BACKGROUND Technical Field

The present disclosure relates to an organic light-emitting diodedisplay device and a test method thereof, and more particularly, to adisplay device and a test method thereof which can realize a narrowbezel by sharing signal application pads for a pixel test and signalapplication pads for a touch block test.

Discussion of the Related Art

A touchscreen panel is an input device through which an instructiondisplayed on a screen of an image display device or the like is selectedusing a user’s hand or an object to input a user command. For this, thetouchscreen panel may be provided on the front face of an image displaydevice to convert a contact point directly coming into contact with auser’s hand or an object into an electrical signal such that aninstruction selected at the contact point can be received as an inputsignal.

The touchscreen panel does not require an additional input device suchas a keyboard or a mouse and thus is increasingly used. Recently, atouchscreen panel has been widely used for flat panel displays such as aliquid crystal display and an OLED display device.

As methods for implementing a touchscreen panel, a resistive overlaytype, a light sensing type, a capacitive type, and the like are known.Among these, a capacitive type touchscreen panel can convert a contactpoint into an electrical signal through a conductive detection patternthat detects changes in capacitance formed with another surroundingdetection pattern or a ground electrode when a human hand or an objecttouches the touchscreen panel.

Such a touchscreen panel is manufactured in such a manner that it isattached to the outer face of a flat panel display, in general. However,when a touchscreen panel is attached to the outside face of a flat paneldisplay, that is, when an add-on type touchscreen panel is manufactured,it is necessary to provide an adhesive layer between the touchscreenpanel and the flat panel display, resulting in deterioration of opticalcharacteristics. Further, a touchscreen panel manufacturing process isrequired separately from a flat panel display manufacturing process, andthus manufacturing time and costs increase. Accordingly, to solve suchproblems, a flat panel display in which a touchscreen panel and adisplay panel are integrated has recently been developed.

Meanwhile, in a touchscreen panel manufacturing process, a touchdetection electrode for detecting touch input is additionally providedto a display element, distinguished from general display elements, andthus a process of testing whether the touch detection electrode hasfailed as well as a process of testing the display element areperformed.

Here, in a panel manufacturing process according to the conventionaladd-on method in which a touchscreen panel is attached to the outer faceof a flat panel display, a step of testing whether a touch detectionelectrode has failed is performed after a step of forming a final moduleor a step of manufacturing a touchscreen panel in units of cells inorder to determine a touch detection function, in general.

SUMMARY

Accordingly, embodiments of the present disclosure are directed to anin-cell touch organic light-emitting diode display device and a testmethod thereof that substantially obviate one or more of the problemsdue to limitations and disadvantages of the related art.

An object of the present disclosure is to provide an in-cell touch OLEDdisplay device and a test method thereof which can reduce a space for abezel for forming lines for testing not only display elements but alsoelectrodes for detecting touch.

Another object of the present disclosure is to provide an in-cell touchOLED display device and a test method thereof which can reduce thenumber of pads for testing defects of display elements and a pluralityof electrodes for detecting touch.

Another object of the present disclosure is to provide an in-cell touchOLED display device and a test method thereof which can increasechamfering efficiency of a glass substrate on which cells are formed.

Additional features and aspects will be set forth in the descriptionthat follows, and in part will be apparent from the description, or maybe learned by practice of the inventive concepts provided herein. Otherfeatures and aspects of the inventive concepts may be realized andattained by the structure particularly pointed out in the writtendescription, or derivable therefrom, and the claims hereof as well asthe appended drawings.

To achieve these and other aspects of the inventive concepts, asembodied and broadly described, an in-cell touch organic light-emittingdiode (OLED) display device comprises: a pixel array including datalines, gate lines intersecting the data lines, a plurality of pixelscorresponding to a plurality of subpixels and arranged in a matrix, anda plurality of touch blocks arranged to respectively correspond to theplurality of pixels; a plurality of test pads arranged in a bezel areaoutside the pixel array and used to selectively perform a pixel test anda touch block test; a plurality of pixel test lines and a plurality oftouch block test lines connected to the plurality of test pads andarranged within the pixel array; a switching unit disposed between theplurality of test pads and the plurality of pixel test lines and theplurality of touch block test lines and applying a test signal to anyone of the pixel test lines and the touch block test lines; a pixel testswitching pad disposed in the bezel area and providing a control signalfor testing pixel operation in the pixel array to the switching unit;and a touch block test switching pad disposed in the bezel area andproviding a control signal for testing the touch blocks within the pixelarray to the switching unit.

In the in-cell touch OLED display device according to the presentdisclosure, the plurality of touch block test lines may be arranged inparallel with the pixel test lines.

The in-cell touch OLED display device according to the presentdisclosure may further include a substrate including driving circuitsfor driving the pixel array, and the plurality of test pads, theswitching unit, the pixel test switching pad and the touch block testswitching pad formed in the bezel area.

In the in-cell touch OLED display device according to the presentdisclosure, a test signal applied to each of the plurality of touchblock test lines may be a constant current.

In the in-cell touch OLED display device according to the presentdisclosure, electrical characteristics of touch blocks measured by theplurality of test pads may include any one of a capacitance value,frequency and resistance voltage of a capacitor formed in the touchblock.

In another aspect, a test method of an in-cell touch OLED display devicecomprises: applying the same test signal to a plurality of pixel testlines connected to a plurality of pixel electrodes arranged in a matrixwithin a pixel array; detecting information on defects of a pixel towhich the test signal is applied; providing a switching signal to aswitching unit to connect a plurality of touch block test lines formedin the pixel array to a plurality of test pads formed in a bezel area;applying the same test signal to the touch block test lines; anddetecting information on defects of a touch block to which the testsignal is applied.

The in-cell touch OLED display device and the test method thereofaccording to the present disclosure can obtain the following effects.

First, pads for a TFT test and pads for a touch block test can beshared.

Second, a degree of freedom in design can be improved by reducing thenumber of required test pads.

Third, a bezel size can be reduced to decrease a cell size andchamfering efficiency of a glass substrate can be improved.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the inventive concepts asclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiments of the disclosure andtogether with the description serve to explain various principles. Inthe drawings:

FIG. 1 illustrates an active area and a non-active area of a displaydevice.

FIG. 2 enlarges “A” of FIG. 1 and illustrates test line arrangement fortest of an in-cell touch OLED display device according to the presentinvention.

FIG. 3 illustrates arrangement of test pads, a switching unit, a pixeltest switching pad and a touch block test switching pad in FIG. 2 .

FIG. 4 is a cross-sectional view of a touch sensor in-cell type organicelectroluminescent device according to an embodiment of the presentinvention.

FIGS. 5A and 5B are schematic cross-sectional views for describingoperation of a touch sensor in the touch sensor in-cell type organicelectroluminescent device.

FIG. 6A is a cross-sectional view taken along line I—I′ of FIG. 2 andFIG. 6B is a cross-sectional view taken along line II—II′ of FIG. 2 .

FIG. 7 is a flowchart showing a test method of the in-cell touch OLEDdisplay device according to the present invention.

FIG. 8A illustrates a glass substrate of a general in-cell touch OLEDdisplay device and FIG. 8B illustrates a glass substrate of the in-celltouch OLED display device according to the present invention.

DETAILED DESCRIPTION

For embodiments of the present invention disclosed in the description,specific structural and functional descriptions are exemplified for thepurpose of describing embodiments of the present invention, andembodiments of the present invention can be implemented in various formsand are not to be considered as a limitation of the invention.

The present invention can be modified in various manners and havevarious forms and specific embodiments will be described in detail withreference to the drawings. However, the disclosure should not beconstrued as limited to the embodiments set forth herein, but on thecontrary, the disclosure is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the embodiments.

While terms, such as “first”, “second”, etc., may be used to describevarious components, such components must not be limited by the aboveterms. The above terms are used only to distinguish one component fromanother. For example, a first component may be referred to as a secondcomponent and the second component may be referred to as the firstcomponent without departing from the scope of the present invention.

When an element is “coupled” or “connected” to another element, itshould be understood that a third element may be present between the twoelements although the element may be directly coupled or connected tothe other element. When an element is “directly coupled” or “directlyconnected” to another element, it should be understood that no elementis present between the two elements. Other representations fordescribing a relationship between elements, that is, “between”,“immediately between”, “in proximity to”, “in direct proximity to” andthe like should be interpreted in the same manner.

The terms used in the specification of the present invention are merelyused in order to describe particular embodiments, and are not intendedto limit the scope of the present invention. An element described in thesingular form is intended to include a plurality of elements unless thecontext clearly indicates otherwise. In the specification of the presentinvention, it will be further understood that the terms “comprise” and“include” specify the presence of stated features, integers, steps,operations, elements, components, and/or combinations thereof, but donot preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or combinations.

Unless otherwise defined, all terms including technical and scientificterms used herein have the same meaning as commonly understood by one ofordinary skill in the art to which example embodiments pertain. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andshould not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Meanwhile, when a certain embodiment can be implemented in a differentmanner, a function or an operation specified in a specific block may beperformed in a different sequence from that specified in a flowchart.For example, two consecutive blocks may be simultaneously executed orreversely executed according to related function or operation.

Hereinafter, an in-cell touch OLED display device and a test methodthereof according to the present invention will be described withreference to the attached drawings.

FIG. 1 illustrates an active area and a non-active area of a displaydevice.

As shown, the display device includes an active area A/A (or pixel area)in which an image is displayed by a plurality of pixel circuits disposedand a non-active area N/A (or bezel area) in which integrated circuitsfor driving the pixel circuits disposed in the active area A/A, and thelike are disposed. The plurality of pixel circuits include a pixel arrayand a plurality of pixels.

FIG. 2 enlarges “A” of FIG. 1 and illustrates test line arrangement fortest of an in-cell touch OLED display device according to the presentinvention.

As shown, the in-cell touch OLED display device according to the presentinvention includes: a pixel array 200 having data lines, gate linesintersecting the data lines, a plurality of pixels P11...Pmn (m, n eachis an integer greater than 1) corresponding to a plurality of subpixelsand arranged in a matrix, and a plurality of touch blocks disposed torespectively correspond to the plurality of pixels; a plurality of testpads 220 arranged in a bezel area outside the pixel array and used toselectively perform a pixel test and a touch block test; a plurality ofpixel test lines 250 and a plurality of touch block test lines 260connected to the plurality of test pads 220 and arranged in the pixelarray; a switching unit 240 which is disposed between the plurality oftest pads 220 and the plurality of pixel test lines 250 and touch blocktest lines 260 and applies a test signal to any one of the pixel testlines and the touch block test lines; a pixel test switching pad 210which is disposed in the bezel area and provides a control signal fortesting pixel operation in the pixel array 200 to the switching unit240; and a touch block test switching pad 230 which is disposed in thebezel area and provides a control signal for testing touch blocks in thepixel array 200 to the switching unit 240.

The plurality of touch block test lines 260 is arranged in parallel withthe pixel test lines 250.

The in-cell touch OLED display device includes a substrate includingdriving circuits for driving the pixel array 200 and the plurality oftest pads 220, the switching unit 240, the pixel test switching pad 210and the touch block test switching pad 230 formed in the bezel area.

FIG. 3 illustrates arrangement of the test pads 220, the switching unit240, the pixel test switching pad 210 and the touch block test switchingpad 230 in FIG. 2 .

As shown, the switching unit 240 includes a plurality of first switchingtransistors T1 which receives an operation signal provided from thepixel test switching pad 210 through gate electrodes thereof, and aplurality of second switching transistors T2 which receives an operationsignal provided from the touch block test switching pad 230 through gateelectrodes thereof. When a gate on voltage is supplied to the gateelectrodes of the first switching transistors T1 through the pixel testswitching pad 210, a gate off voltage is supplied to the gate electrodesof the second switching transistors T2 through the touch block testswitching pad 230. When the gate on voltage is supplied to the gateelectrodes of the first switching transistors T1 through the pixel testswitching pad 210 to turn on the first switching transistors T1, testpads 220-1, 220-2, 220-3, ..., 220-n are connected to the pixel testlines 250. Here, the plurality of second switching transistors T2 isturned off. On the other hand, when the gate on voltage is supplied tothe gate electrodes of the plurality of second switching transistors T2through the touch block test switching pad 230, the plurality of secondswitching transistors T2 is turned on and thus the test pads 220-1,220-2, 220-3, ..., 220-n are connected to the touch block test lines260. Here, the plurality of first switching transistors T1 is turnedoff.

FIG. 4 is a cross-sectional view of a touch sensor in-cell type organicelectroluminescent device according to an embodiment of the presentinvention. Here, an area in which a switching thin film transistor (TFT)will be formed is defined as a switching area and an area in which adriving TFT will be formed is defined as a driving area DA forconvenience of description.

As shown, the touch sensor in-cell type organic electroluminescentdevice 101 according to the present invention includes a first substrate110 on which a driving TFT DTr, a switching TFT (not shown), an organiclight emitting diode (OLED) E, and a touch sensor are formed, and asecond substrate 170 for encapsulation. First, a configuration of thefirst substrate 110 will be described.

A semiconductor layer 113 formed of pure polysilicon and composed of afirst region 113 a serving as a channel and positioned at the center andsecond regions 113 b positioned on both sides of the first region 113 aand doped with impurities in high concentration is formed on the firstsubstrate 110 in each pixel region P. A gate insulating layer 116 isformed on the overall surface of the first substrate 110 to cover thesemiconductor layer 113, and a gate electrode 120 corresponding to thefirst region 113 a of the semiconductor layer 113 is formed on the gateinsulating layer 116.

Semiconductor contact holes 125 for respectively exposing the secondregions 113 b positioned on both sides of the first region 113 a areformed in an interlayer insulating layer 123 and the gate insulatinglayer 116 formed thereunder.

Source and drain electrodes 133 and 136 are formed to respectively comeinto contact with the second regions 113 b exposed through thesemiconductor contact holes 125. The source and drain electrodes 133 and136, the semiconductor layer 113 including the second regions 113 b incontact with the source and drain electrodes 133 and 136, the gateinsulating layer 116 and the gate electrode 120 formed on thesemiconductor layer 113 constitute the driving TFT DTr.

A first electrode 147 connected to the drain electrode 136 of thedriving TFT DTr serves as an anode or a cathode according to the type ofthe driving TFT DTr. The first electrode 147 connected to the drivingTFT DTr serves as the anode in the present embodiment.

A first passivation layer 140 is formed on the overall surface of thedriving TFT DTr. A drain contact hole 143 for exposing the drainelectrode 136 of the driving TFT DTr is formed in the first passivationlayer 140.

The first electrode 147 connected to the drain electrode 136 of thedriving TFT DTr through the drain contact hole 143 is formed on thefirst passivation layer 140 including the drain contact hole 143 in eachpixel region P. A buffer pattern 150 is formed on the first electrode147 at the boundary of each pixel region P in such a manner that thebuffer pattern 150 surrounds each pixel region P while being superposedon the edge of the first electrode 147. In each pixel region Psurrounded by the buffer pattern 150, an organic emission layer 155 isformed on the first electrode 147 and a second electrode 158 is formedon the organic emission layer 155 in the entire active area. The firstand second electrodes 147 and 158 and the organic emission layer 155formed therebetween constitute the OLED E.

The second electrode 158 formed on the organic emission layer 155 may beformed of a metal material having a relatively low work function value,for example, one of aluminum (Al), an aluminum alloy (AINd), silver(Ag), magnesium (Mg), and aluminum magnesium alloy (AlMg), to serve as acathode.

A second passivation layer 160 is formed of an inorganic insulatingmaterial or an organic insulating material on the second electrode 158formed in the entire active area in order to improve optical efficiencyof the organic emission layer 155, protect the second electrode 158 andprevent permeation of moisture.

A touch second electrode 165 in the form of bars spaced at predeterminedintervals is formed on the second passivation layer 160. Here, the touchsecond electrode 165, the second passivation layer 160 positioned underthe touch second electrode 165, and the second electrode 158 (touchfirst electrode) formed in the entire active area constitute a touchsensor TS.

The second electrode 158 is characterized in that it serves as acomponent of the OLED E and a component of the touch sensor TS.

The second substrate 170 for encapsulation which is formed of atransparent glass material or a transparent plastic material is providedon the touch second electrode 165 having an inert gas, an organicinsulating material or a face seal interposed therebetween. A polarizer175 may be provided on the outside face of the second substrate 170 toimprove efficiency of light emitted from the organic emission layer 155.

Meanwhile, in the touch sensor in-cell type organic electroluminescentdevice 101 having the above-described configuration according to thepresent invention, the touch sensor TS is configured as a capacitorcomposed of the second electrode 158, the second passivation layer 160and the touch second electrode 165. When a finger touches the capacitor,the capacitor recognizes capacitance variation due to fringe fieldvariation thereof and thus serves as a touch sensor TS.

FIGS. 5A and 5B are cross-sectional views for describing operation ofthe touch sensor in the touch sensor in-cell type organicelectroluminescent device according to the present invention. Forconvenience of description, the driving and switching TFTs and the OLEDare omitted and only the touch sensor included in the first substrateand the second substrate for encapsulation are briefly illustrated.

As shown in FIG. 5A, when the surface of the second substrate 170 is nottouched by a user’s finger 195 in the touch sensor in-cell type organicelectroluminescent device 101, a fringe field formed between the secondelectrode 158 and the touch second electrode 165 is maintained uniformand capacitance does not vary, and thus touch operation is notperformed. As shown in FIG. 5B, when the surface of the second substrate170 is touched by the user’s finger 195, the fringe field between thesecond electrode 158 (touch first electrode) and the touch secondelectrode 165 varies due to the touching of the finger 195, and thus thetouch sensor TS detects the touch and performs touch operation.

Referring to FIG. 4 , the touch sensor in-cell type organicelectroluminescent device 101 having the above-described configurationaccording to the present invention is obtained by forming the secondelectrode 158 that is a component of the OLED E as a touch firstelectrode of the touch sensor TS, forming the second passivation layer160 on the second electrode 158 to prevent moisture infiltration as adielectric layer, separately forming the touch second electrode 165 inthe form of spaced bars on the second passivation layer 160, and thenattaching the second substrate 170 for encapsulation thereto.

FIG. 6A is a cross-sectional view taken along line I—I′ of FIG. 2 andFIG. 6B is a cross-sectional view taken along line II—II′ of FIG. 2 . Asshown in FIG. 6A, a control signal for testing pixel operation in thepixel array 200 is provided to the switching unit 240 through the pixeltest switching pad 210 via a pixel test signal transmission line 211. Aplurality of switching transistors T1 in the switching unit 240 connectsa test pad signal line 221 to the plurality of pixel test lines 250formed in the pixel array 200.

As shown in FIG. 6B, a control signal for testing touch blocks in thepixel array 200 is provided to the switching unit 240 through the touchblock test switching pad 230 via a touch block test signal transmissionline 231. A plurality of switching transistors T2 in the switching unit240 connects the test pad signal line 221 to the plurality of touchblock test lines 260 formed in the pixel array 200. A touch areaincludes a touch metal layer 303 disposed on a touch buffer layer 301,an interlayer insulating layer 302 interposed between the touch bufferlayer 301 and the touch metal layer 303, and a passivation layer 304disposed on the touch metal layer 303. 401 denotes a material being usedto be as a bank and 402 denotes a material being used to be a spacer ina peripheral area of the active area. As shown in FIG. 6B, the touchmetal layer 303 comes into contact with a source/drain region of a TFTin a region “B”.

FIG. 7 is a flowchart showing a test method of the in-cell touch OLEDdisplay device according to the present invention.

The same pixel test signal is supplied to the plurality of pixel testlines connected to the plurality of pixel electrodes arranged in amatrix in the pixel array. That is, a control signal for testing pixeloperation in the pixel array 200 is provided to the switching unit 240through the pixel test switching pad 210 via the pixel test signaltransmission line 211. Accordingly, a switching transistor T1 in theswitching unit 240 connects the test pad signal line 221 to the pixeltest lines 250 (S1).

The same operating power is supplied to all pixels through all datalines such that all pixels of the pixel array 200 emit light. Here,defective pixels that do not operate although a test signal is appliedthereto are detected (S2).

Upon completion of pixel test, a control signal or switching signal fortesting touch blocks in the pixel array 200 is provided to the switchingunit 240 through the touch block test switching pad 230 via the touchblock test signal transmission line 231, i.e., switching test signal.Accordingly, the switching transistor T2 in the switching unit 240connects the test pad signal line 221 to the plurality of touch blocktest lines 260 formed in the pixel array (S3).

Accordingly, a constant current is applied to the plurality of touchblock test lines from the test pads 220 through the test pad signal line221, i.e., supplying touch block test signal (S4).

After the test signal is applied to the touch blocks of the pixel arraythrough the touch block test lines, electrical characteristics of thetouch blocks are measured through the test pads to detect defects oftouch blocks or detect defective touch blocks. Here, the measuredelectrical characteristics of the touch blocks may include any one of acapacitance value, frequency and resistance voltage of a capacitorformed in the touch blocks (S5).

FIG. 8A illustrates a glass substrate of a general in-cell touch OLEDdisplay device and FIG. 8B illustrates a glass substrate of the in-celltouch OLED display device according to the present invention.

In a display panel of a general in-cell touch OLED display device, padsfor applying a test signal are formed in an area around cells for a testthrough lighting after the cells are manufactured. Accordingly, a spacefor forming touch test pads, touch block test lines, pixel test pads andpixel test lines is required in a bezel. Since the size of each celldisposed in a glass substrate C is large, the number of cells that canbe formed in a single glass substrate C decreases. Accordingly, theefficiency of the glass substrate forming a panel decreases.

On the other hand, touch test pads for touch block test and pixel testpads can be shared in the in-cell touch OLED display device according tothe present invention, and thus the number of required test pads can bereduced and a cell size is not increased. Accordingly, a larger numberof cells can be formed in the glass substrate C of the in-cell touchOLED display device according to the present invention.

For example, when the area of the glass substrate is “C”, 20 cells (1Ato 5D)can be formed on the glass substrate in the case of theconventional in-cell touch OLED display device because the cell sizeincreases, as shown in FIG. 8A.

In the case of the in-cell touch OLED display device according to thepresent invention, a cell size is not increased and thus 30 cells (1 ato 6 e) can be formed on the glass substrate C, as shown in FIG. 8B.Accordingly, design efficiency can be improved and manufacturing costscan be reduced.

The features, structures and effects described in the aforementionedexample of the present application are included in at least one exampleof the present application and are not limited to only one example.Furthermore, features, structures and effects exemplified in at leastone example of the present application can be combined with otherexamples or modified by those skilled in the art. Accordingly, it isintended that the present invention cover such combination andmodification.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the in-cell touch organiclight-emitting diode display device and the test method thereof of thepresent disclosure without departing from the spirit or scope of thedisclosure. Thus, it is intended that the present disclosure cover themodifications and variations of this disclosure provided they comewithin the scope of the appended claims and their equivalents.

What is claimed is:
 1. An organic light-emitting diode (OLED) displaydevice, comprising: a pixel array disposed in a pixel area and includingdata lines, a plurality of pixels, a plurality of touch sensors arrangedon a first passivation layer, and an encapsulation layer on theplurality of touch sensors; a plurality of test pads arranged in a bezelarea outside the pixel area and configured to selectively perform apixel test and a touch sensor test; a plurality of pixel test lines anda plurality of touch sensor test lines connected to the plurality oftest pads and arranged in the pixel array; a switching part disposedbetween the plurality of test pads and the plurality of pixel test linesand the plurality of touch sensor test lines and configured to apply atest signal to at least one of the plurality of pixel test lines and theplurality of touch sensor test lines; and at least one dam between thepixel area and the bezel area, wherein a touch sensor among theplurality of touch sensors comprises: a buffer layer; a metal layer onthe buffer layer; an interlayer insulating layer on the metal layer; anda second passivation layer on the metal layer, and wherein the bufferlayer and the second passivation layer extend to the bezel area over theat least one dam.
 2. The OLED display device of claim 1, wherein theplurality of touch sensor test lines are arranged in parallel with theplurality of pixel test lines.
 3. The OLED display device of claim 1,wherein the plurality of test pads comprise: a first pad disposed in thebezel area and configured to provide a control signal for testing pixeloperation in the pixel array to the switching part; and a second paddisposed in the bezel area and configured to provide a control signalfor testing the touch sensors in the pixel array to the switching part.4. The OLED display device of claim 3, further comprising: a substrateincluding driving circuits configured to drive the pixel array andfurther including the plurality of test pads and the switching part inthe bezel area.
 5. The OLED display device of claim 3, wherein thecontrol signal for testing the touch sensors in the pixel array isprovided to the switching part through the second pad via a signaltransmission line.
 6. The OLED display device of claim 3, wherein atouch routing line is disposed at the first passivation layer.
 7. TheOLED display device of claim 1, wherein a test signal applied to each ofthe plurality of touch sensor test lines is a constant current.
 8. TheOLED display device of claim 1, wherein electrical characteristics ofthe touch sensor measured by one of the plurality of test pads includeat least one of a capacitance value, a frequency, and a resistancevoltage of a capacitor in the touch sensor.
 9. The OLED display deviceof claim 8, further comprising: an OLED in the pixel area, wherein theOLED and the capacitor share one electrode.
 10. The OLED display deviceof claim 9, wherein the other electrode of the capacitor is in a form ofspaced bars.
 11. The OLED display device of claim 9, wherein the otherelectrode of the capacitor is disposed on the first passivation layer.12. The OLED display device of claim 9, wherein the capacitor isconfigured to recognize a capacitance variation due to fringe fieldvariation thereof caused by a touch and to serve as a touch sensor. 13.The OLED display device of claim 1, wherein the metal layer contactswith a source or drain region of a thin film transistor in the pixelarea.
 14. The OLED display device of claim 1, wherein the buffer layeris disposed on the first passivation layer.
 15. The OLED display deviceof claim 1, wherein the first passivation layer is formed of an organicinsulation material or an inorganic insulation material.
 16. The OLEDdisplay device of claim 15, wherein the buffer layer is disposed on theinorganic insulation material of the first passivation layer.
 17. TheOLED display device of claim 1, wherein the first passivation layer isdisposed in the entire pixel area.
 18. The OLED display device of claim1, wherein the encapsulation layer is a substrate provided on oneelectrode of the touch sensor.
 19. The OLED display device of claim 18,wherein the encapsulation layer is formed of a transparent glassmaterial or a transparent plastic material.